Active oxygen species adsorbed on the catalyst surface and its effect on formaldehyde oxidation over Pt/TiO2 catalysts at room temperature; role of the Pt valence state on this reaction?

Abstract

Pt/TiO₂ catalysts, prepared by reduction pretreatment, showed enhanced catalytic activities in formaldehyde oxidation. X-ray photoelectron spectroscopy analysis confirmed that catalytic activity was affected by Pt valence states in the Pt/TiO₂ catalyst. Using O₂ re-oxidation tests, we showed that there was a correlation between the area of oxygen consumed and the ratio of metallic Pt species on the catalyst surface. The O₂ re-oxidation ability was involved in the production of the adsorbed formate intermediate from HCHO, confirmed through diffuse reflectance infrared Fourier transform spectroscopy analysis. Furthermore, metallic Pt species were involved in the oxidation of adsorbed CO to CO₂.